Computer-aided diagnosis method and computer-aided diagnosis apparatus therefor

ABSTRACT

A Computer-Aided Diagnosis (CAD) apparatus for correctly detecting a nodule is provided. The CAD apparatus includes an input device for receiving a first image captured by emitting X-rays towards a user and a second image that is discriminated from the first image and is an image of the user; an information acquisition device for acquiring a bone model of the user by using the second image; and a CAD device for compensating for the first image by using the bone model.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims priority from Korean Patent Application No.10-2011-0123115, filed on Nov. 23, 2011, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

1. Field

Methods and apparatuses consistent with the exemplary embodiments relateto a computer-aided diagnosis method and a computer-aided diagnosisapparatus therefor, and more particularly, to a computer-aided diagnosismethod for correctly detecting a nodule in a human body and acomputer-aided diagnosis apparatus therefor.

2. Description of the Related Art

Computer-Aided Diagnosis (CAD) systems are used to discover a nodule,such as a cancer, at an early stage from a medical digital X-ray image.

Related art CAD systems are not widely used due to low performance inimage sensitivity and product specification, and accordingly, researchesand developments for enhancing image sensitivity and productspecification have been conducted.

The biggest reason for the low performance of CAD systems may beanatomical noise in a human body to be diagnosed by image capturing. Theanatomical noise may include bones, soft tissues, and blood vessels. Indetail, in an X-ray image, if anatomical noise exists in an area inwhich a nodule exists, the anatomical noise overlaps with the nodule,thereby making detecting the existence of the nodule difficult.

Thus, a CAD method and apparatus for correctly detecting the existenceof a nodule should be provided.

SUMMARY

The exemplary embodiments provide a Computer-Aided Diagnosis (CAD)method for correctly detecting a nodule and a CAD apparatus therefor.

The exemplary embodiments also provide a CAD method for correctlydetecting a nodule by detecting and removing anatomical noise includinga bone and a CAD apparatus therefor.

According to an aspect of the exemplary embodiments, there is provided aComputer-Aided Diagnosis (CAD) apparatus including: an input device forreceiving a first image captured by emitting X-rays towards a user andreceiving a second image that is discriminated from the first image andis an image of the user; an information acquisition device for acquiringa bone model of the user by using the second image; and a CAD device forcompensating for the first image by using the bone model.

The information acquisition device may acquire bone information that isinformation regarding at least one of a position and shape of a bonestructure of the user from the second image, and acquire the bone modelby using the bone information.

The CAD device may remove anatomical noise in the first image bymatching the bone model with the first image.

The CAD device may detect a nodule from the first image from which theanatomical noise has been removed.

The information acquisition device may acquire a bone structure of theuser from the second image, set at least one point in the bonestructure, and generate the bone model including position information ofthe set at least one point.

The second image may include a Computed Tomography (CT) image of theuser, and the information acquisition device may acquire the bone modelcorresponding to a bone structure of the user.

The second image may include a dual energy capturing image of the user,and the information acquisition device may acquire a bone structure ofthe user from a bone image included in the dual energy capturing image,set at least one point in the bone structure, and generate the bonemodel including position information of the set at least one point.

The second image may include a tomosynthesis image of the user, and theinformation acquisition device may acquire a bone structure of the userfrom a bone image included in the tomosynthesis image, set at least onepoint in the bone structure, and generate the bone model includingposition information of the set at least one point.

The CAD apparatus may further include an output device for displayingthe compensated first image.

The first image may be a chest X-ray image captured by emitting X-raystowards a chest of the user, and the bone model may be a rib cage modelof the user.

According to another aspect of the exemplary embodiments, there isprovided a Computer-Aided Diagnosis (CAD) method for diagnosing adisease using a CAD apparatus, the CAD method including: receiving afirst image captured by emitting X-rays towards a user and receiving asecond image of the user that is discriminated from the first image;acquiring a bone model of the user by using the second image; andcompensating for the first image by using the bone model.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects will become more apparent by describing indetail exemplary embodiments thereof with reference to the attacheddrawings in which:

FIG. 1 is an X-ray image;

FIGS. 2A and 2B are block diagrams of Computer-Aided Diagnosis (CAD)apparatuses according to exemplary embodiments of the application;

FIG. 3 is a block diagram of a CAD apparatus according to anotherexemplary embodiment of the application;

FIGS. 4A to 4C are diagrams for describing an operation of the CADapparatus of FIG. 3;

FIGS. 5A to 5C are images for describing another operation of the CADapparatus of FIG. 3;

FIG. 6 is a diagram for describing a bone model acquired by aninformation acquisition device in the CAD apparatus of FIG. 3;

FIGS. 7A and 7B are images for describing another operation of the CADapparatus of FIG. 3;

FIGS. 8A to 8C are diagrams for describing another operation of the CADapparatus of FIG. 3; and

FIG. 9 is a flowchart illustrating a CAD method according to anexemplary embodiment of the application.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

In detail, the present application provides an apparatus and method fordetecting a nodule from a chest X-ray image. When the chest X-ray imageis read to detect a nodule, a rib cage may hide the nodule, therebydecreasing a possibility of detecting the nodule, e.g., a lung nodule.

In addition, it is difficult to correctly determine a shape and positionof the rib cage only with the chest X-ray image.

Thus, the present application provides a Computer-Aided Diagnosis (CAD)apparatus capable of increasing a nodule detection performance bycorrectly acquiring a rib cage of a user from which the nodule isdetected. Hereinafter, a CAD method for increasing a nodule detectionperformance according to an exemplary embodiment and a CAD apparatustherefor are described in detail with reference the accompanyingdrawings.

Expressions such as “at least one of,” when preceding a list ofelements, modify the entire list of elements and do not modify theindividual elements of the list.

FIG. 1 is an X-ray image 100.

Referring to FIG. 1, the X-ray image 100 is captured by emitting X-rays,radioactive rays, towards a chest of a user. The X-ray image 100includes bones, blood vessels, and soft tissues of the human body.

A rib cage 112 is above an area 110 in which a nodule 111 exists. Therib cage 112 disturbs detection of the nodule 111, and is noise in theX-ray image 100 from which the nodule 111 is supposed to be detected.Thus, it is difficult to separately extract the rib cage 112 from theX-ray image 100.

FIGS. 2A and 2B are block diagrams of CAD apparatuses according to theexemplary embodiments of the application. FIG. 2A is a block diagram ofa CAD apparatus 210 according to an exemplary embodiment, and FIG. 2B isa block diagram of a CAD apparatus 250, according to another exemplaryembodiment.

Referring to FIG. 2A, the CAD apparatus 210 includes an input device215, an information acquisition device 220, and a CAD device 225.

The input device 215 receives a first image captured by emitting X-raystowards a user, and a second image that is discriminated from the firstimage and is an image of the user.

Although it is illustrated in FIG. 2A that the input device 215 receivesan input signal IN including the first image and the second image, theinput device 215 may capture and generate the first image and the secondimage itself and output the first image and the second image to theinformation acquisition device 220. For example, the input device 215may include an X-ray capturing camera (not shown) and a second imagecapturing camera (not shown) and may generate the first image with theX-ray capturing camera and the second image with the second imagecapturing camera.

The information acquisition device 220 acquires a bone model of the userby using the second image input from the input device 215. The bonemodel is obtained by reproducing a bone structure of the user capturedin the first image. The information acquisition device 220 may extractor acquire the bone structure of the user who is a capturing object ofthe first image from the second image discriminated from the firstimage.

The information acquisition device 220 may acquire bone information thatis information regarding at least one of a position and shape of thebone structure of the user from the second image and generate the bonemodel by using the bone information. An operation of the informationacquisition device 220 for generating the bone model is described inmore detail below with reference to FIGS. 5A to 8C.

The CAD device 225 compensates for the first image by using the bonemodel acquired by the information acquisition device 220. In detail, theCAD device 225 may remove anatomical noise in the first image bymatching the bone model acquired by the information acquisition device220 with the first image. The anatomical noise indicates a human tissue,such as a bone, obstructing detection of a nodule from an X-ray image.The CAD device 225 outputs a diagnosis image OUT from which theanatomical noise in the first image has been removed.

The CAD device 225 may detect a nodule from the diagnosis image OUTcorresponding to the first image from which the anatomical noise hasbeen removed. The detection of the nodule from the first image fromwhich the anatomical noise has been removed may cause detection accuracyto increase compared with a case of detecting the nodule from theoriginal first image.

Referring to FIG. 2B, the CAD apparatus 250 further includes an outputdevice 270, compared to the CAD apparatus 210 shown in FIG. 2A.

Since an input device 255, an information acquisition device 260, a CADdevice 265 in FIG. 2B correspond to the input device 215, theinformation acquisition device 220, and the CAD device 225 in FIG. 2A,respectively, repeated descriptions thereof are omitted.

The output device 270 displays the diagnosis image OUT that is thecompensated first image. In detail, the output device 270 includes adisplay panel (not shown) to display the diagnosis image OUT through thedisplay panel so that the user visually recognizes the diagnosis imageOUT.

FIG. 3 is a block diagram of a CAD apparatus 300 according to anotherexemplary embodiment.

Referring to FIG. 3, the CAD apparatus 300 includes an input device 310,an information acquisition device 320, and a CAD device 330. The CADapparatus 300 may further include an output device 340.

Since the input device 310, the information acquisition device 320, andthe CAD device 330 included in the CAD apparatus 300 correspond to theinput device 215, the information acquisition device 220, and the CADdevice 225 included in the CAD apparatus 210, respectively, and theoutput device 340 of FIG. 3 corresponds to the output device 270 of FIG.2B, repeated descriptions thereof are omitted.

The input device 310 includes a first input device 311 and a secondinput device 312.

The first input device 311 receives a first image IN1 captured byemitting X-rays towards a user. Although it is illustrated in FIG. 3that the first input device 311 receives the first image IN1, the firstinput device 311 may include an X-ray capturing camera (not shown) togenerate the first image IN1 itself.

The second input device 312 receives a second image IN2 that isdiscriminated from the first image IN1 and is an image obtained bycapturing the user. Although it is illustrated in FIG. 3 that the secondinput device 312 receives the second image IN2, the second input device312 may include a second image capturing camera (not shown) to generatethe second image IN2 itself. The second image IN2 is an image of theuser who is a capturing object of the first image IN1, and may includeat least one of a Computed Tomography (CT) image, a dual energycapturing image, and a tomosynthesis image. The second image IN2 mayalso include an image captured in another capturing scheme.

The first image IN1 and the second image IN2 may be an image obtained bycapturing a chest area of the user.

The input device 310 transmits the first image IN1 to the CAD device 330and transmits the second image IN2 to the information acquisition device320.

The information acquisition device 320 may acquire a bone structure ofthe user from the second image IN2, set at least one point in the secondimage IN2, and generate a bone model including position information ofthe set at least one point. The bone model will be described in detailwith reference to FIGS. 4A to 6.

In detail, the information acquisition device 320 may include a boneinformation acquisition device 321 and a model acquisition device 322.

The bone information acquisition device 321 acquires bone informationthat comprises information regarding at least one of a position andshape of the bone structure of the user.

The model acquisition device 322 may acquire the bone model by using thebone information output from the bone information acquisition device321.

A detailed operation of the information acquisition device 320 isdescribed in detail below with reference to FIGS. 4A to 4C.

The CAD device 330 compensates for the first image IN1 by using the bonemodel transmitted from the model acquisition device 322. In detail, theCAD device 330 outputs a read image OUT in which it is easy to detect anodule by removing anatomical noise in the first image IN1.

FIGS. 4A to 4C are diagrams for describing an operation of the CADapparatus 300 of FIG. 3.

FIG. 4A illustrates the first image IN1 input to the first input device311, FIG. 4B illustrates the bone model acquired by the modelacquisition device 322, and FIG. 4C illustrates the read image OUToutput from the CAD device 330.

Referring to FIG. 4A, an X-ray image 410 that is the first image IN1obtained by capturing the chest of the user is output from the firstinput device 311 and transmitted to the CAD device 330.

Referring to FIG. 4B, the information acquisition device 320 acquiresbone information that is information regarding at least one of aposition and shape of a bone structure of the user from the second imageIN2 and generates a bone model by using the bone information.

The bone model shown in FIG. 4B may include position information of thebone structure of the user. The information acquisition device 320extracts a bone structure from the second image IN2. Alternatively, theinformation acquisition device 320 may predict and generate a bonestructure from an image related to bones included in the second imageIN2. The information acquisition device 320 may set at least one pointV1, V2, P1, P2, P3, P4, P5, and P6 in the extracted or generated bonestructure and generate a bone model including position information ofthe set at least one point V1, V2, P1, P2, P3, P4, P5, and P6.

The position information included in the bone model may be informationobtained by expressing the at least one point V1, V2, P1, P2, P3, P4,P5, and P6 existing on the bone structure as coordinates when the bonestructure is three-dimensionally modeled. For example, when apredetermined point on the bone structure is set as a central point (0,0, 0) of x-, y-, and z-axes, coordinate values corresponding to the atleast one point V1, V2, P1, P2, P3, P4, P5, and P6 may be generatedbased on the set central point (0, 0, 0). Accordingly, the bone modelshown in FIG. 4B may include position information of the bone structureand predetermined points on the bone structure.

The CAD device 330 compensates for anatomical noise in the first imageIN1 by matching the bone model with the first image IN1. In detail, theCAD device 330 may remove a bone image from the first image IN1 bymatching the bone model with the first image IN1 based on a position.

Referring to FIG. 4C, the CAD device 330 may adjust brightness of a ribcage to clearly view nodules 441 and 451 at points 440 and 450.

FIGS. 5A to 5C are images for describing another operation of the CADapparatus 300 of FIG. 3. In detail, FIGS. 5A to 5C are diagrams fordescribing an operation of the information acquisition device 320 whenthe second image IN2 is a CT image.

FIG. 5A illustrates a CT image 510 that is the second image IN2, FIG. 5Billustrates a bone structure reproduced by using the second image IN2,and FIG. 5C illustrates that at least one point is set on the bonestructure.

Referring to FIG. 5A, the CT image 510 is obtained by capturing thechest of the user. The CT image 510 is transmitted as the second imageIN2 from the input device 310 to the information acquisition device 320.

Referring to FIG. 5B, the information acquisition device 320 generates arib cage structure 520 that is a bone structure of the chest by usingthe CT image 510. In detail, the bone information acquisition device 321may acquire information regarding at least one of a position and shapeof a rib cage included in the CT image 510 and may generate a bonestructure by using the acquired information. Since embodying the ribcage structure 520 using the CT image 510 is disclosed in the paperissued in the Society for Photographic and Instrumentation Engineers(SPIE) 2010 by Lee and Reeves, a detailed description thereof is omittedherein.

Referring to FIG. 5C, the information acquisition device 320 sets atleast one point V1, V2, P1, P2, P3, P4, and P5 on the bone structure520. The at least one point V1, V2, P1, P2, P3, P4, and P5 may bereference points for matching a bone model with the first image IN1.

FIG. 6 is a diagram for describing a bone model acquired by theinformation acquisition device 320 in the CAD apparatus 300 of FIG. 3.

Referring to FIG. 6, the information acquisition device 320 may generatea bone model including position information, e.g., coordinateinformation, by using the bone structure 520, as shown in FIG. 5C, onwhich the at least one point V1, V2, P1, P2, P3, P4, and P5 are set. Indetail, the model acquisition device 322 may generate a rib cage modelthat is a bone structure existing in the chest.

FIGS. 7A and 7B are images for describing another operation of the CADapparatus 300 of FIG. 3. In detail, FIGS. 7A and 7B are diagrams fordescribing an operation of the information acquisition device 320 whenthe second image IN2 is a dual energy capturing image. The dual energycapturing image indicates an image including an image captured byemitting high-energy X-rays and an image captured by emitting low-energyX-rays when an X-ray image is captured by emitting radioactive raystowards a chest.

When the chest is captured by emitting high-energy X-rays, an image inwhich soft tissues excluding bones are clearly viewed is generated. Inaddition, when the chest is captured by emitting low-energy X-rays, animage in which bones are clearly viewed is generated.

FIG. 7A illustrates an image 710 captured by emitting low-energy X-raysamong the dual energy capturing image. The input device 310 transmitsthe image 710 to the information acquisition device 320.

FIG. 7B illustrates that at least one point is set on the image 710. Theinformation acquisition device 320 may set points for marking positionsin the image 710 in the same manner as described with reference to FIG.5C. Since setting predetermined points in the image 710 is the same asdescribed with reference to FIG. 5C, a detailed description thereof isomitted herein.

The information acquisition device 320, specifically, the modelacquisition device 322 of the information acquisition device 320, mayembody the bone model described in FIG. 6 by using an image 720 in whichpredetermined points are set.

FIGS. 8A to 8C are diagrams for describing another operation of the CADapparatus 300 of FIG. 3. In detail, FIGS. 8A to 8C are diagrams fordescribing an operation of the information acquisition device 320 whenthe second image IN2 is a tomosynthesis image. FIG. 8A illustrates howto capture a tomosynthesis image, FIG. 8B illustrates a plurality ofimages generated by capturing the tomosynthesis image, and FIG. 8Cillustrates that a bone structure is embodied and predetermined pointsare set by using the tomosynthesis image.

Referring to FIG. 8A, a tomosynthesis image capturing device 810captures a user who is a capturing object by placing the user on adetector and moving a position of an X-ray tube 811.

In detail, the user is captured while moving the X-ray tube 811 topoints P11, P12, and P13.

Referring to FIG. 8B, a plurality of images are captured by using thetomosynthesis image capturing device 810. In detail, a tomosynthesisimage 830 includes a plurality of images 831, 832, and 833 correspondingto various capturing points P11, P12, and P13, respectively.

A bone structure may be generated by using the plurality of images 831,832, and 833 of the tomosynthesis image 830.

Referring to FIG. 8C, the information acquisition device 320 generates athree-dimensional bone structure image 860 and sets predetermined pointsin the bone structure image 860. Since setting the predetermined pointsis the same as described in FIG. 5C, a detailed description thereof isomitted herein.

As described above with reference to FIGS. 5A to 8C, by using the firstimage IN1, which is an X-ray image, and an image different from thefirst image IN1, a bone structure or a bone model of the user may becorrectly extracted. That is, according to the present application, anaffection of anatomical noise in an X-ray image may be reduced bygenerating a bone model using an image obtained by capturing the sameuser and compensating for an image of a bone included in the first imageIN1, that is an X-ray image, by using the generated bone model.Accordingly, accuracy of reading a nodule using X-rays may increase.

FIG. 9 is a flowchart illustrating a CAD method 900 according to anexemplary embodiment. The CAD method 900 may be performed by the CADapparatus 210, 250, or 300 according to an exemplary embodiment and hasthe same technical spirit as that of an operation of the CAD apparatus210, 250, or 300 according to an exemplary embodiment. Thus, thedescription made in FIGS. 2A to 8C is not repeated herein. Hereinafter,the CAD method 900 will now be described with reference to the CADapparatus 300 according to another exemplary embodiment.

Referring to FIG. 9, in operation 910, a first image IN1, captured byemitting X-rays towards a user, and a second image IN2, that isdiscriminated from the first image IN1 and is an image of the user, arereceived. Operation 910 may be performed by the input device 310.

In operation 920, a bone model of the user is acquired by using thesecond image IN2. Operation 920 may be performed by the informationacquisition device 320, in detail, the bone information acquisitiondevice 321.

In detail, in operation 920, bone information that is informationregarding at least one of a position and shape of a bone structure ofthe user is acquired from the second image IN2. The bone model may beacquired by using the acquired bone information.

Alternatively, in operation 920, the bone structure of the user may beacquired from the second image IN2, at least one point may be set on thebone structure, and the bone model including position information of theat least one set point may be generated.

In operation 930, the first image IN1 is compensated for by using thebone model generated in operation 920. Operation 930 may be performed bythe information acquisition device 320, or specifically, the modelacquisition device 322 of the information acquisition device 320.

In detail, operation 930 may include removing anatomical noise in thefirst image IN1 by matching the bone model generated in operation 920with the first image IN1 (although not shown).

The CAD method 900 may further include detecting a nodule from the firstimage IN1 from which the anatomical noise has been removed (although notshown).

The CAD method 900 may further include displaying a diagnosis image OUTthat is the compensated first image generated in operation 930 (althoughnot shown).

While the application has been particularly shown and described withreference to exemplary embodiments thereof, it will be understood bythose of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the exemplary embodiments as defined by the following claims.

What is claimed is:
 1. A Computer-Aided Diagnosis (CAD) apparatuscomprising: an input device which receives a first image of a usercaptured by emitting X-rays towards the user, and receives a secondimage of the user that is discriminated from the first image; aninformation acquisition device which acquires a bone model of the userbased on the second image; and a CAD device for compensating for thefirst image based on the bone model.
 2. The CAD apparatus of claim 1,wherein the information acquisition device acquires bone informationregarding at least one of a position and shape of a bone structure ofthe user from the second image, and acquires the bone model based on thebone information.
 3. The CAD apparatus of claim 1, wherein the CADdevice removes anatomical noise in the first image by matching the bonemodel with the first image.
 4. The CAD apparatus of claim 3, wherein theCAD device detects a nodule from the first image from which theanatomical noise has been removed.
 5. The CAD apparatus of claim 1,wherein the information acquisition device acquires a bone structure ofthe user from the second image, sets at least one point in the bonestructure, and generates the bone model including position informationof the set at least one point.
 6. The CAD apparatus of claim 5, whereinthe second image includes a Computed Tomography (CT) image of the user,and the information acquisition device acquires the bone modelcorresponding to the bone structure of the user.
 7. The CAD apparatus ofclaim 5, wherein the second image includes a dual energy capturing imageof the user, and the information acquisition device acquires the bonestructure of the user from a bone image included in the dual energycapturing image, sets the at least one point in the bone structure, andgenerates the bone model including the position information of the setat least one point.
 8. The CAD apparatus of claim 5, wherein the secondimage includes a tomosynthesis image of the user, and the informationacquisition device acquires the bone structure of the user from a boneimage included in the tomosynthesis image, sets the at least one pointin the bone structure, and generates the bone model including theposition information of the set at least one point.
 9. The CAD apparatusof claim 1, further comprising an output device which displays thecompensated first image.
 10. The CAD apparatus of claim 1, wherein thefirst image is a chest X-ray image captured by emitting X-rays towards achest of the user, and the bone model is a rib cage model of the user.11. A Computer-Aided Diagnosis (CAD) method for diagnosing a diseaseusing a CAD apparatus, the CAD method comprising: receiving a firstimage of a user captured by emitting X-rays towards the user, andreceiving a second image of the user that is discriminated from thefirst image; acquiring a bone model of the user based on the secondimage; and compensating for the first image by using the bone model. 12.The CAD method of claim 11, wherein the acquiring of the bone model ofthe user comprises: acquiring bone information regarding at least one ofa position and shape of a bone structure of the user from the secondimage; and acquiring the bone model based on the bone information. 13.The CAD method of claim 11, wherein the compensating of the first imagecomprises removing anatomical noise in the first image by matching thebone model with the first image.
 14. The CAD method of claim 13, furthercomprising detecting a nodule from the first image from which theanatomical noise has been removed.
 15. The CAD method of claim 11,wherein the acquiring of the bone model of the user comprises: acquiringa bone structure of the user from the second image; setting at least onepoint in the bone structure; and generating the bone model includingposition information of the set at least one point.
 16. The CAD methodof claim 15, wherein the second image includes at least one of aComputed Tomography (CT) image of the user, a dual energy capturingimage of the user, and a tomosynthesis image of the user.
 17. The CADmethod of claim 11, further comprising displaying the compensated firstimage.
 18. The CAD method of claim 11, wherein the first image is achest X-ray image captured by emitting X-rays towards a chest of theuser.
 19. A computer-aided apparatus (CAD) for diagnoising a disease,the apparatus comprising: a first input device which receives a firstimage of a user captured by emitting X-rays towards the user; a secondinput device which receives a second image of the user; a boneinformation acquisition device which acquires bone information from thesecond image; a model acquisition device which acquires a bone modelbased on the acquired bone information, and a CAD unit which compensatesfor the first image based on the bone model.
 20. The apparatus of claim19, wherein the second image comprises an image of the user who is acapturing object of the first image, and is at least one of a ComputedTomography (CT) image, a dual energy capturing image, and atomosynthesis image.